The present invention relates to a fuel-injection type 2-stroke engine and an ignition-combustion method of a fuel-injection type 2-stroke engine.
As is known to those skilled in the art, a spark-ignition type 2-stroke engine, in which fuel is injected into the cylinder of the engine, has an advantage in that the amount of fuel escaping into the exhaust port can be considerably reduced and, as a result, good thermal efficiency and good exhaust emission can be obtained when the engine is operating under a medium or a heavy load. However, if such a 2-stroke engine is operating under a light load, it is difficult to maintain stable combustion. Therefore, in a conventional 2-stroke engine, in order to obtain stable combustion when the engine is operating under a light load, the engine is operated by using a rich air-fuel mixture or the start of combustion is delayed by greatly retarding the ignition timing. As a result of this, in a conventional 2-stroke engine, in spite of injecting fuel into the cylinder of the engine, there are drawbacks in that when the engine is operating under a light load, thermal efficiency is reduced and, in addition, the amount of harmful components, such as carbon monoxide and hydrocarbon, in the exhaust gas is increased.